Copper oxide rectifier



Sept. 14, 19 48. cL P 2,449,453

COPPER OXIDE RECTIFIER I Filed Dec. 51, 1946 1 INVENTOR. Rmm po (m p fi mm,

ATTORNEY Patented Sept. 14, 1948 COPPER OXIDE RECTIFIER Richard H. Clapp, Danvers, Mass, assigno'r to Sylvania Electric Products Inc, Salem, Mass, a corporation of Massachusetts Application December 31, 1946, Serial No. 719,610

This invention relates to metal rectifiers, and

particularly to copper oxide rectifiers, and to their method of manufacture.

2 Claims. (Cl. 175-366) Such rectifiers are ordinarily made by oxidizing a normally fiat annular copper blank. I have found, however, that the rectification can be greatly improved by using "dished or, curved copper blanks and oxidizing them on the convex side.

An object of the present invention is therefore a more efficient rectifier, and a feature of the invention is a dished annular blank oxidized on its convex side. Other objects features and advantages of the invention will be apparent from the following specification, taken in connection with the accompanying drawings in which:

Figure 1 is an unoxidized copper blank according to the invention drawn partly cut away to show the copper and oxide layers in section;

Figure2 is the blank after oxidization and cooling, drawn partly cut away to show the copper and oxide layers in section; and

Figure 3 is the blank as straightened by compression.

' about 1000 C.

cess of oxidizing gas to the other side, for example,

On cooling, the curvature of the blank becomes accentuated because of the greater contraction.

of the copper in relation to the copper-oxide surface, the copper oxide surface thereby being put in compression to about the same degree as though the blank had not been preformed.

However, on assembling these discs in-a rectifier unit, sufficient pressure is customarily applied to flatten all the discs, to the form shown in Figure 3, the copper being soft-annealed by the temperature of oxidation. With my preformed disc, more straightening action is required than with the usual originally-fiat discs and consequently the copper oxide is put into greater compression.

i have found that this increase in compression gives as much as .a 40% increase in rectifying ratio over the standard flat blanks. This greatly increases the usefulness of the rectifier.

What I claim is: v

1. The method of making a copper oxide rectifier blank which comprises dishing a copper blank to form having a convex and a concave side, oxidizing said blank on theconvex side at high temperature, and compressing itto a final flat form.

, 2. The method of claim 1, in which the high temperature at which the blank is oxidized is RICHARD H. cLArP.

REFERENCES CITED I The following references are of record in the file of this patent: 

